Dynamic nuclear polarization induced by breakdown of fractional quantum Hall effect

TL;DR

This study investigates how dynamic nuclear polarization (DNP) occurs during the breakdown of fractional quantum Hall states, revealing dependence on current sweep rates and contrasting polarities with integer quantum Hall states.

Contribution

It demonstrates that DNP during FQH breakdown depends on sweep rates and exhibits opposite polarity compared to integer quantum Hall states, providing new insights into quantum Hall breakdown mechanisms.

Findings

Voltage-current characteristics depend on sweep rates at FQH states.

DNP polarity in FQH breakdown is opposite to that in integer QH breakdown.

DNP occurs in the breakdown regime of fractional quantum Hall states.

Abstract

We study dynamic nuclear polarization (DNP) induced by breakdown of the fractional quantum Hall (FQH) effect. We find that voltage-current characteristics depend on current sweep rates at the quantum Hall states of Landau level filling factors $\nu$ = 1, 2/3, and 1/3. The sweep rate dependence is attributed to DNP occurring in the breakdown regime of FQH states. Results of a pump and probe experiment show that the polarities of the DNP induced in the breakdown regimes of the FQH states is opposite to that of the DNP induced in the breakdown regimes of odd-integer quantum Hall states.